1.Seven bridges spanned the River Pregel,

Many more than might have been expected;

Königsberg’s wise leaders were delighted

To have built such very splendid structures.2.Crowds each ev’ning surged towards the river,

People walked bemused across the bridges,

Pondering a simple-sounding challenge

Which defeated them and left them puzzled.3.Here’s the problem; see if you can solve it!

Try it out at home an scraps of paper!

STARTING OUT AND ENDING AT THE SAME SPOT,

YOU MUST CROSS EACH BRIDGE JUST ONCE EACH EV’NING.Refrain:

Eulerian graphs all have this restriction:

THE DEGREE OF ANY POINT IS EVEN.

That’s the oldest graph result

That mankind has ever known.4.All the folk in Königsberg were frantic!

All their efforts ended up in failure!

Happily, a learn-ed math’matician

Had his house right there within the city.5.Euler’s mind was equal to the problem:

“Ah”, he said, “You’re bound to be disheartened.

Crossing each bridge only once per outing

Can’t be done, I truly do assure you.”Refrain:

Eulerian graphs…6.Laws of Nature never can be altered,

We can’d change them, even if we wish to.

Nor can flooded rivers or great bridges

Interfere with scientific progress.7.War brought strife and ruin to the Pregel;

Bombs destroyed those seven splendid bridges.

Euler’s name and fame will, notwithstanding,

Be recalled with Königsberg’s for ever.Refrain:

Eulerian graphs…8.Thanks to Euler, Graph Thry is thriving.

Year by year it flourishes and blossoms,

Fertilising much of mathematics

And so rich in all its applications.9.Colleagues, let us fill up all our glasses!

Colleagues, let us raise them now to toast the

Greatness and the everlasting glory

Of our Graph Thry, which we love dearly!

# “Seven bridges spanned the River Pregel…”

Graph Theory Hymn

by Zdenĕk Ryjáček

by Bohdan Zelinka

by Donald A. Preece

mathematics, graph theory, Leonhard Euler, Eulerian graph, Koenigsberg bridge problem